# CVE-2026-66421: OpenClaw Dashboard Stored XSS via lastMessage Session Field

> Unauthenticated attackers can inject malicious scripts into session transcripts, leading to admin session hijacking and unauthorized modification of agent instructions.

- **Severity:** High 8.8 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 30 Jul 2026
- **Updated:** 24 Sep 2026
- **Also known as:** GHSA-hc44-65x2-rvc2

## What is CVE-2026-66421?

CVE-2026-66421 is a high-severity cross-site scripting vulnerability in tugcantopaloglu openclaw-dashboard, published on 30 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

OpenClaw Dashboard contains a stored cross-site scripting vulnerability that allows unauthenticated remote attackers to execute arbitrary JavaScript in the administrator's browser session by injecting HTML markup into agent transcript messages processed through the sessions API. Attackers can craft a message containing inline event handler payloads such as an img tag with an onerror attribute within the 60-character rendering budget, which is stored in the session transcript and interpolated unsanitized into innerHTML on the default landing page, allowing theft of session tokens and unauthorized calls to authenticated administrative endpoints including agent instruction file modification.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-66421?

It affects 1 product.


Products: Tugcantopaloglu Openclaw Agent Dashboard.

## How do I fix CVE-2026-66421?

No fix has been published for CVE-2026-66421 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-66421 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-66421 exists.

Public exploit code:

- Security Advisory: Stored Cross-Site Scripting Via Agent Messages Leading To Session Token Theft (openclaw-dashboard) (github_poc): https://github.com/theopaid/CVE-2026-66421-OpenClaw-Dashboard-Stored-XSS-via-lastMessage-Session-Field

## Other vulnerabilities in tugcantopaloglu openclaw-dashboard

- [CVE-2026-66418](https://insights.sbomify.com/CVE-2026-66418/): OpenClaw Dashboard v3.0.0 Stored XSS via Failed Login Username Field (critical 9.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-66421 and fix it if it is affected.

What it is: CVE-2026-66421 is a high-severity cross-site scripting vulnerability in tugcantopaloglu openclaw-dashboard, published on 30 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-66421 exists.

Affected product: tugcantopaloglu openclaw-dashboard. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-66421/ (Markdown: https://insights.sbomify.com/CVE-2026-66421/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-66421
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-66421
- OSV: https://osv.dev/vulnerability/CVE-2026-66421

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-66421/
Summaries are generated and may contain mistakes; the official description above is the record.